The Nature of the Beast (according to Susan McCarthy)

Where do codfish get their food? Where does the town of Nahant get its revenue?

When I was a child in Massachusetts, my mother and her best friend used to visit the tidepools at Nahant. They kept salt-water aquariums at a time when no one did that, and they peopled these artificial tidepools with native creatures they collected. Usually they took their children with them, which included me and my best friend Molly.

When those days vanished in puffs of smoke – divorces, remarriages, moves across country – the visits to the tidepools ended for Molly. Three thousand miles away, my mother started over with Pacific tidepools. The only relationship that endured was the friendship between Molly and me.

Recently I visited Molly in Massachusetts. Her mother died some years ago, and when I persuaded Molly that we should revisit the tidepools, no one could tell us exactly where on Nahant we had gone. On the only available day, we went to the Nahant peninsula at low tide.

We drove around looking for rocky shores with tidepools. We asked a jogger if she knew where there were tidepools, or where we could park so we could look. She said “Nahant's a great town, but it's not very friendly to people who want to park.” She didn't know what to suggest.

When we came to East Point, I was pretty sure we had found the place. The minute you see East Point, you know it has great tidepools among its tumbles of big rocks festooned with seaweed. But those tidepools are next to Northeastern University's Marine Science Center (which didn't exist when I was a kid). You can drive out there, but they won't let you park. It's miles out, at the end of the peninsula, surrounded by lovely seascapes and No Parking signs, another of the scenes of my childhood that's off limits.

We parked anyway.

A field trip of high school kids was there. Most were only interested in jumping from rock to rock and climbing the cliffs. We met one intelligent boy who had figured out the best ways to locate crabs and was happy to pass along his discoveries. When angry teachers made the class leave because a few kids misbehaved, Molly and I had it to ourselves.

Molly examined a pool with a deep, irregular crevice on one side. “There's something in here,” she said. We could just see two suspicious eyes peering back at us. A crab? A shrimp? Neither of us felt like sticking our fingers in to be pinched. On dry land we might have put a small stick in the crevice to see if the creature would grab it and be pulled out. “The thing about tidepools is there are no sticks lying around,” Molly noted.

Cracks in the rocks were filled with clusters of small gold snails. There were little dark green crabs. There were mussels and barnacles and limpets. There were small sea urchins, banded with white and tan and pale green. There were pink five-rayed starfish. One silver dollar-sized starfish had four long rays and one extremely short one that was regenerating after some unfortunate incident. There were pink algae like the algae in California, both the kind that makes a flat crust on rocks or shells and the foliose kind like pink parsley. They seemed like they might be a slightly different pink than the California kind, a bit more of a salmon color, but I couldn't be sure.

We had to hurry away, but I found great things under the last few rocks. Under one were two little crabs feasting on a pulled-off claw from a big crab. Under another were two eel-shaped fish like California blennies, with elegant narrow vertical stripes on the dorsal fin. Under a third was something I had never seen in the Pacific: a baby lobster, three or four inches long, holding up its claws in case it needed to pinch me. It was a handsome, subtly-colored creature, and the minute I saw its suspicious eyes I knew that the creature Molly had found peering from the crevice had also been a baby lobster.

From talking to my mother and looking at Molly's mother's notebook, it seems that they never found lobsters at Nahant back in the day. On the web I found some recent research saying you can find baby lobsters in the intertidal zone (research about how to do a lobster census). I also read that the main predators of baby lobsters are codfish. I knew that overfishing had drastically reduced the number of cod in the last few decades. I also knew that the lobster fishery was in great shape, catching lots of lobsters. So I suspect that the reason our families hadn't found baby lobsters at Nahant years ago was that the cod had been getting them. The fact that Molly and I found lobsters may be a sign of codfish in trouble.

In the short time we had been out on the rocks we had gotten a parking ticket.

The Dangerous Lives of Treeshrews

I was reading Tupai: A Field Study of Bornean Treeshrews by Louise H. Emmons because that is the kind of thing I like, and learned about the absentee maternal system found in some treeshrew species.

First I should say that treeshrews are the same as tree shrews, and the closing up of the word is probably meant to indicate that they don't really live in trees and they're not really shrews. This is a case of TC, Taxonomic Correctness, like the argument that you should call a starfish a sea star because it's not really a fish. Oh please. But a big issue about treeshrews is whether they're descended from very primitive primates and so are our distant cousins, or whether the connection goes further back so that the primates and the treeshrews are both descended from the clade Euarchonta, making them even more distant cousins. I have no opinion on this.

In the absentee maternal system the mother treeshrew builds two nests (yeah, in trees). They are far apart. She puts her babies in one and she sleeps in the other one when she's not racing around snuffling through the leaf litter and catching bugs. Every other day she secretly visits the babies, taking a different route each time, and nurses them. When she's not there the babies lie still and don't make a sound. If an intrepid wildlife biologist like Louise H. Emmons takes a baby out of the nest, it lies silently in her hand with its eyes closed.

One day when they are old enough the mother treeshrew drops by as usual, but instead of just nursing them she takes them out and shows them Borneo. Here's a bug, here's a little trail, here's what you do when you hear a scary noise -- there's another bug! Let me see you grab it! She brings them with her on her rounds and protects them while they learn the business of treeshrewing.

According to a report from the wild, the babies were "shaky" the first time they came out of the nest hole.

The reason treeshrews do this has to be that it makes it much less likely that predators will find the nest and eat the babies by observing the mother. (That's the sort of creepy trick that jays and crows do, for example.) And obviously it's very convenient for the mother treeshrew. Which makes me lean toward the idea that treeshrews aren't primates – what baby primate holds that still for that long?

Like other wildlife biologists who write books for general audiences, Louise H. Emmons tries to find a balance between the stuff working scientists mostly do, and the stuff that people are actually interested in hearing about. Most of the work of wildlife biology doesn't involve playing peekaboo with baby gorillas, swimming with whale sharks, or filming hippo hijinks. It involves data sets. Perhaps Emmons leans too far in the direction of hard science, because her best story was walled up alive in an appendix. (I read appendices so you don't have to. Or at least I skim them.)

In Appendix 1, Emmons explains why a trapping data set is incomplete.

 

In the January trapping period, a group of elephants went through the study area, systematically destroying man-made objects (rain gauges, signs, trail markers, etc.). They stomped on seven baited traps but interestingly did not step on one that contained a treeshrew, while flattening the two on each side (trapping in January was curtailed, and this month is excluded from most data).

 

The elephants spared the tiny prisoner! Of course I think they did it because they felt compassion for the treeshrew, but I realize that there is also a compelling quality to  the explanation that they did it because they didn't want to get their feet sticky.